Sulphonic ester coupler



Patented July 14, 1942 UNITED-STATES PATENT OFFICE sunrnomc Esrua cournsa v Willard D. Peterson, Rochester, N. Y., assignor to Eastman Kodak Companmnochestc r, N. Y., a

corporation of New Jersey No Drawing. Application September 26, 1940, Serial No. 358,492. In Great Britain January Claims. 11. 95-6) This invention relates to color-forming development and particularly to novel coupling components for producing colored images.

It is known that colored photographic images may be formed by using a developer which forms a colored compound on development. The col stitute. desirable couplers. I The couplers contain- -ing the sulphonic ester group are generally rendered less soluble by the incorporation of this group and are, therefore, satisfactory for the preparation of couplers for incorporation in photographic emulsions. They are, however, sumored compound thus formed is deposited adjacent to the silver grains of thesilver image during the development. It is also known that a colored image may be formed by adding to certain developer solutions or by incorporating in the gelatino-silver-halide emulsion before or after exposure a, compound which couples during clently soluble for use in developing solutions.

, The introduction of the sulphonic ester group development with the oxidation product of the developing agent, and forms a coloring substance which is likewise deposited adjacent to the silver grains of the silver image during development. Such a compound, which is employed in conjunction with a developing agent for the silver and which couples with the oxidation product thereof during development, is referred to herein as a coupling component or coupler.

The present. invention concerns new or improved color forming developerscomprising a primary aromatic/amino compound serving as the developing agent, and a coupler as hereinafter defined and also includes a new or improved color development process which consists in developing a reducible silver salt image in a photographic element with the aid of a primary aromatic amino compound in the presence tends to confer better dispersability on the. coupier-molecule, which is a desirable pr p rty when the coupler is to be'incorporated in emulsions. The compounds which I propose to use have the following general formula:

wherein R=aryl or alkyl but does not contain a coupling function, l

, R'=an organic radical containing a coupling of a coupler. as hereinafter defined. It also includes photographic sensitive elements having" such a coupler incorporated in one ormore emulsion layers.

In British Patent 503,752 sulphonic ester couplers are described which are obtained by the reaction of u-n'aphthol sulphonic acid chloride with phenols having a high "molecular substituted amino or.hydroxy group. In these ecu-'- plers the hydroxyl group of the naphthol constitutes the coupling function and the sulphur atom of the sulphonicester group is directly at-' tached to the coupler portion of the molecule. While these compounds form colored photo'- graphic images upon development in primary aromatic amino developers, the coupler molecule in certain cases is unstable and is unsatis factory for that reason.

I have .found that sulphonic ester couplers in which the sulphur atom of the sulphonic ester group is not directly attached to a portion of the molecule containing a coupling function, that a reactive methylene or phenolic hydroxyl group are relatively stable compounds and. confunction, a that is a reactive methylene or phenolic hydronl group. Specific compounds which may be used according to my invention are the following:

i-hydroxy-6-naphthyl-p-tolnene sulphonate %-OC NHCOCHICOCH:

p-aoctoacetaniinophenyl benzene sulphonate O V o m o z-acetyl-tfl-beusoylacetamimpbenyl-iyeoumnronyl sulphonic ethylacetoacetate to introduce the coupling function and cause the formation of the sulphonic ester coupler.

The couplers made according to my invention may be dissolved in the developing solution or may be incorporated in the emulsion layer according to their solubility characteristics. The compounds indicated by the first two examples are suitable for use in the developing solution and those of the. last two examples maybe incorporated in the emulsion layer.

As stated above, the coupler must contain a coupling function but this coupling function may not be attached to the sulphur atom of the sulphonic ester group. By "coupling function I mean a functional or reactive group common to coupler compounds which react with primary aromatic amino developing agents. This reactive group takes the form of a reactive methylene or reactive ethanol group. By "reactive methylene" I mean a CH: group whcih is reactive in the coupling process. The CH: group is usually present between two negative centers as in the groups -co-cm-co cncm cnf or in a ring Such examples of ring systems are oxindole and pyrazolone. One of the hydrogen atoms of the methylene group may, in 40 formula:

general, be substituted by a polar group without destroying the chemical activity of the group. By "reactive ethanol" I mean the group This group occurs in the phenolic and naphtholic coupler compounds which are presumably active in the or pposition with respect to the position of the hydronl group.

The coupling compounds used according to my invention may contain other substituents which do not affect the coupling properties of the compound. Where I refer ingeneral formula to aryl and alkyl groups, it is to be understood that these groups may be further substituted provided that the other requirements with respect to coupling aremet. The aromatic amino, developing agents used with the coupler compounds of my invention include the mono-, diand tri-aminoaryl com-- pounds and their derivatives formed by substitution in the amino group as well as in the ring, such as alkylphenylenediamines and alkyltoluylenediamines.

and their substitution products may also be used where the amino group is unsubstituted. All of these compounds have an unsubstituted amino group which enables the oxidation products of the developer to couple with the color-forming compounds to form a dye image.

The following developer formulas may be used with the compounds of my invention:

A. p-Aminodiethylaniline sulphate grams 2 Sodium sulphite anhydrous do 5 Sodium carbonate anhydrous do 20 Potassium bromide do 2 Water to liter 1 B. Coupler grams 1 to 5 Isopropyl alcohol cc 100 B is added to A My development process may be employed for the production of colored photographic images in layers of gelatin or other carrier such as collodion, organic esters of cellulose or synthetic resins. The carrier may be supported by a transparent medium such as glass, a cellulose ester, or a non-transparent reflecting medium such as paper of an opaque cellulose ester. v The emulsion may be coated as a single layer on the support or as superposed layers on one or both sides of the support. The superposed layers may be differentially sensitized to form' natural color photographic images in the well known manner. The examples and compounds set forth in the present specification are illu'strativeonly and it is to be understood that myinvention is limited only by the scope of the appended claims. "'vIclaim: 4

1. A color forming photographic developer, comprising a primary aromatic amino developing agent and a coupler compound having the where R is selected from the class consistin of alkyl and aryl radicals not containing a coupling function and R is an organic radical containin at east one group selected from the class consisting of methylene and ethenol which is reactive with primary aromatic amino developing agents.

2. A color forming photographic developer, I

comprising a primary aromatic amino developing agent and a coupler compound having the formula:

where R. is selected from the class consisting of alkyl and aryl radicals not containing a coupling function and R is an organic radical comprising a reactive ethenol coupling function.

3. A color forming photographic developer,

. comprising a primary aromatic amino developing agent and a coupler compound having the a formula where R is selected from the .class consisting of ing an acetamino group.

function and is alkyl and aryl radicals not containing a pling function and R is a naphthol.

5. A color forming photographic developer, comprising a primary aromatic amino developing agent and a coupler-compoundhaving the formula:

R-SOa-O-R' where R is selected from the class consisting of' alkyl and aryl radicals not containing a coupling function and R is an organic radical compris- 6. A color forming photographic developer comprising a primary aromatic amino developing agent and 1-hydroxy-5-naphthyl-p-to1uene-' sulphonate as a coupling compound. n

7. A color forming photographic developer comprising a primary aromatic amino developing agent and p-acetoacetamino phenylbenzenesulphonate as a coupling compound.

8. The method of producing a colored photographic image in a gelatino-silver halide emulsion layer which comprises exposing the layer and developing it with a primary aromatic amino developing agent in the presence of a coupler, com ound having the formula:

7 having the formula:

where R; is selected from the class consisting of alkyl and aryl radicals not containing a coupling an organic radical containing at least one group selected from the .class consisting of methylene and ethenol which is reactive with primary aromatic amino developing agents.

9. A photographic emulsion for forming colored images comprising a carrier containing a sensitive silver halide and a coupler compound n so -o-a' where R is selected from the class consistin .of alkyl and aryl radicals not containing a coupling function and R is an organic radical containing at least one group selected from the class consisting of methylene and ethenol which is reactive with primary aromatic amino developing agents.

10. A photographic emulsion for forming colcred images comprising a gelatino-silver halide emulsion having incorporated therein a coupler compound of the general-formula:

where R is selected from the class consisting of alkyl and aryl radicals'not containing a coupling function and R is an organic radical containing at least one group selected from the class con-v sisting of methylene and ethenol which is reactive with primary aromatic amino developing agents. WILLARD D. PETERSON. 

